Management of a One-wall Intrabony Osseous Defect with Combination of Platelet Rich Plasma and Demineralized Bone Matrix- a Two-year Follow up Case Report.

Periodontal regeneration in a one-wall intrabony defect is a challenging and complex phenomenon. The combination therapy of commercially available bone grafts with the innovative tissue engineering strategy, the platelet rich plasma, has emerged as a promising grafting modality for two and three walled intrabony osseous defects. The application of this combination approach was attempted in a most challenging one-wall intrabony defect. Open flap debridement and placement of combination of autologous platelet rich plasma(PRP) and demineralized bone matrix was done in one-wall intrabony defect in relation to tooth #21 in a 30 year old female patient. The 6-month follow- up results showed significant improvement in clinical parameters. Radiographic evidence of bone formation was observed as early as 3 months with almost complete fill by 6 months post-operatively. The results were maintained over a period of 2 years.


Introduction
Periodontal regeneration is defined histologically as regeneration of the tooth's supporting tissues, including alveolar bone, periodontal ligament, and cementum over previously diseased root surface. [1] Periodontal regeneration in intrabony defects has been successfully attempted with a variety of different approaches. Hemiseptal defects i.e., vertical defects in the presence of adjacent roots and where half of a septum remains on the tooth, represents a special case of one-wall defects and the treatment is always a challenge despite the various periodontal regenerative therapies.
Regenerative therapy is strongly superior when compared to open flap debridement alone and a wide array of graft materials have been applied and evaluated clinically, including autogenous bone grafts, allografts and alloplasts. [2] Demineralized freeze-dried bone allograft (DFDBA), which is shown to be both osteocon-ductive and osteoinductive, has been used alone and in combination with other treatment modalities for periodontal therapy. [3] Histologic evidence of periodontal regeneration, including new bone, periodontal ligament and cementum formation has been reported for demineralized freeze-dried bone allografts. [4] The platelet rich plasma (PRP) is an innovative tissue engineering strategy in boosting the periodontal wound healing and periodontal regeneration. [5] The growth factors within PRP like platelet derived growth factor (PDGFaa, PDGFbb, and PDGFab), transforming growth factor beta (TGF-β1, TGFβ2), vascular endothelial growth factor (VEGF), epithelial growth factor (EGF), and insulin-like growth factor (IGF-1) produce a multitude of effects. PDGF is a potent mitogenic and chemotactic factor for both fibroblasts and osteoblasts.
In vivo studies have shown PDGF to stimulate bone formation and consistently enhance wound fill. [6] TGF Many studies have shown that the combination of PRP with demineralized bone matrix is effective in treating periodontal two and three walled intrabony defects. [8][9][10][11] The aim of present study is to assess the effectiveness of a combined regenerative therapy consisting of bone graft and PRP in a clinically challenging one-wall intrabony defect.

Results
The healing was uneventful, indicating biocompatibility of both grafting modalities. The patient showed good compliance and satisfactory oral hygiene maintenance during the course of observation period.  Figure 6).

Discussion
Regeneration of tooth supporting structures destroyed by periodontitis is a major goal of periodontal therapy  This report is mainly concerned with the healing of one-wall intraosseous bony defect of more than 4mm depth and 37 o defect angle. Though there are indications that two and three walled bony defects respond better to regenerative therapy than one-wall defects, several studies have demonstrated that the extent of vertical attachment gain [13][14] or osseous filling [13,[15][16] correlates with the total corono-apical extent of the bony defects, including the one-wall component. In other words, the deeper the bony defect (>4mm), [18][19] [17] The DFDBA and PRP combination is more effective for the treatment of infrabony defects in terms of amount of CAL gain, PPD reduction, and bone fill. [9] PRP, as used in this study, may affect the wound healing not only by a release of PGFs from platelets, but also because of other physical and chemical properties.
The PRP preparation because of its high fibrin content, presents a sticky characteristic that works as a hemostatic and stabilizing agent and may aid blood clot and bone graft immobilization in the defect area.
Blood clot immobilization has been suggested as an important event in the early phases of wound healing in periodontal regenerative procedures. [18] Clinical studies evaluating the combination of PRP and DFDBA showed successful periodontal regeneration in two and three wall intrabony defects. [8][9][10][11] A histologic study by Jung seok lee et al., [19] in a onewall intrabony defect showed that customized n-HA block could provide the space for periodontal tissue engineering with minimal inflammation.
In this case, the DFDBA graft with PRP was sufficient to fill the one wall intrabony defect with predictable healing and improvement in clinical parameters and the results were maintained for a longer period.

Conclusion
Within the limits of present case report, it can be concluded that the combination therapy of platelet rich plasma (PRP) with demineralized bone grafts holds a promising potential for CAL gain, PPD reduction, and bone fill even in a one-wall intrabony defect.
However, further long term clinical research with larger sample size and confirmatory histological evaluations and advanced radiodiagnostical assessment can provide a greater insight to better assess the clinical benefits and actual regenerative process of the combination approach using PRP with bone graft.